netdev - [PATCH] d44: the poll handler b44_poll must not enable IRQ unconditionally

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Message-Id: <1253153447.24160.12.camel@dengdd-desktop>
Date:	Thu, 17 Sep 2009 10:10:47 +0800
From:	DDD <Dongdong.deng@...driver.com>
To:	davem@...emloft.net, mpm@...enic.com, romieu@...zoreil.com
Cc:	netdev@...r.kernel.org
Subject: [PATCH] d44: the poll handler b44_poll must not enable IRQ
	unconditionally

net/core/netpoll.c::netpoll_send_skb() calls the poll handler when
it is available. As netconsole can be used from almost any context,
IRQ must not be enabled blindly in the NAPI handler of the driver
which supports netpoll.

Call trace:
netpoll_send_skb()
{
local_irq_save(flags)
  -> netpoll_poll()
    -> poll_napi()
      -> poll_one_napi()
        -> napi->poll()
            -> b44_poll()
local_irq_restore(flags)
}

Signed-off-by: Dongdong Deng <dongdong.deng@...driver.com>
---
 drivers/net/b44.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index 0189dcd..e046943 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -847,23 +847,22 @@ static int b44_poll(struct napi_struct *napi, int budget)
 {
 	struct b44 *bp = container_of(napi, struct b44, napi);
 	int work_done;
+	unsigned long flags;
 
-	spin_lock_irq(&bp->lock);
+	spin_lock_irqsave(&bp->lock, flags);
 
 	if (bp->istat & (ISTAT_TX | ISTAT_TO)) {
 		/* spin_lock(&bp->tx_lock); */
 		b44_tx(bp);
 		/* spin_unlock(&bp->tx_lock); */
 	}
-	spin_unlock_irq(&bp->lock);
+	spin_unlock_irqrestore(&bp->lock, flags);
 
 	work_done = 0;
 	if (bp->istat & ISTAT_RX)
 		work_done += b44_rx(bp, budget);
 
 	if (bp->istat & ISTAT_ERRORS) {
-		unsigned long flags;
-
 		spin_lock_irqsave(&bp->lock, flags);
 		b44_halt(bp);
 		b44_init_rings(bp);
-- 
1.6.0.4


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